The present invention relates to an anti-graffiti coating material for protecting surfaces of concrete, brick, limestone, slate, wood, metal and the like from graffiti and other markings and to a method of protecting surfaces by treating them with the anti-graffiti coating material.
In recent years, there has been increasing concern over the escalating problem of graffiti. One particular area of concern is the defacing of porous surfaces, such as surfaces of concrete, brick, limestone, slate, wood and masonry. Due to the high porosity of such surfaces, the graffiti is absorbed into the surface to a substantial degree, thereby making it difficult to remove.
As used in the specification and claims, the term "graffiti" means any unwanted painting, drawing, lettering or other marking formed on a surface. Graffiti is typically applied using paints, usually applied by spray cans, or markers. The paints are typically oil-based paints including enamels, epoxies, lacquers and urethanes. The markers are typically color markers having pigmented dyes with fast drying solvents.
In attempting to cope with the graffiti problem, much emphasis has been placed on cleaning techniques for use in treating surfaces to remove graffiti. A common technique is to apply a coating of paint remover, such as methylene chloride, benzene or tolulene. After the coating sits for awhile, it is removed by power washing. This process may be repeated two to four times. Any graffiti residue is then removed by sandblasting or sanding, which may require refinishing of the surface to restore it to its former appearance. Another technique for coping with graffiti is to simply repaint the surface, which is disadvantageous because of the time and expense involved. The use of paint removers is disadvantageous and results in the release of harmful vapors which are detrimental to both health and environment. In addition, paint removers tend to soften and remove the underlying paint.
Specialized cleaning compositions have been developed for removing graffiti. Examples of such cleaning compositions are disclosed in U.S. Pat. No. 5,024,780 to Leys. These cleaning compositions are designed for graffiti removal and not as anti-graffiti protective coatings. Anti-graffiti protectants for use as protective coatings have also been developed. These protectants have not proved satisfactory for several reasons: they are not effective against all types and colors of graffiti; they are expensive to manufacture; they are difficult to apply, usually requiring clean, oil-free and dry surfaces; they cannot be applied to painted surfaces; and they are environmentally unfriendly, often having high volatile organic content.